Considering the lightweight of modular multilevel converter (MMC) and the requirement of DC-side pole-to-ground fault ride-through with the highest probability of occurrence, the fault ride-through problem of half-wave alternating modular multilevel converter (HA-MMC) under pole-to-ground fault needs to be solved urgently. In this paper, the DC-side pole-to-ground fault characteristics of HA-MMC are analyzed on the basis of its topology as well as its working principle, and its fault current expression is derived. A fast ride-through strategy for pole-to-ground DC short-circuit fault is proposed based on the blocking mechanism and switching coordination, which can quickly clear the fault current under the low impedance connection on the AC side to avoid tripping of the AC circuit breaker. Finally, the correctness of the fault characteristic analysis and the effectiveness of the proposed fault protection strategy are verified by simulation.